Microflow restrictors are commonly used in the medical field in conjunction with infusion pump systems to regulate the flow of medicine and other fluids to a patient. Microflow restrictors are typically able to regulate fluid flow in the range of less than 500 milliliters per hour, but can regulate higher rates of flow if necessary. Typical pressures under which infusion pump systems operate are less than about 60 kPa.
Considerable difficulties with existing microflow restrictors are recognized in the prior art. Specifically, with regard to maintaining flow through the restrictor over time, prior art microflow restrictors are believed to be highly susceptible to seizing due to the presence of microparticulates and bubbles in the fluid. The small amount of fluid flowing through the restrictor and the minimal operating pressures of infusion pumps is believed to provide insufficient pressure to move or otherwise overcome the particulates or break the bubbles and permit fluid to continue to flow through the restrictor. To address this issue, select prior art microflow restrictors have been specifically designed to create multiple tortuous paths for fluid, such paths designed to break bubbles and permit particulates to be circumvented by the fluid.
However, prior art flow restrictors are expensive to manufacture due to the very small fluid pathways utilized. Some existing flow restrictors are manufactured using costly processing and post-processing steps. In addition, existing flow restrictors suffer from decreasing flow rates over time due to micro leaks within the flow restrictors.